The legend
of origin of the Grzymala clan who took over the same crest goes:

Some authorities believe that this coat of arms was brought to Poland
from Germany by a knight named Zylberschweg or Zelberszwecht. It is, however,
one of the oldest Polish coats of arms, whose clan's war cry was Grzymal/a
(for Thunder). The original homeland of this clan was the district of
L/omz'a in Masovia. The coat of arms was later augmented by a man in full
battle armor standing in the gate, whose left arm held a shield, whose
right arm held a raised sword. This augmentation was received by Przecl/aw
Grzymal/a, for his courageous defense of the city Pl/ock in 1078 against
the Jatwings from Prince Wl/adisl/aw Hermann.

Subsequently
the coat of arms was also abated: Prince Boleslaw Wstydliwy of Poland
(1127-1179), exiled the knight Grzymal/a, owner of Gos'lice in the Palatinate
of Pl/ock, on the suspicion of treacherous dealings with Prince Kazimierz
of Kujaw, and as further evidence of the Prince's displeasure closed the
gate in this knight's coat of arms.

A second
(though positive) abatement also occurred: When the Lithuanians along
with the Jatwings attacked Masovia, a Grzymal/a, owner of Zielony and
Slasy, courageously stood against them, inflicted a defeat upon them and
hunted them down. For which feat of arms, the coat of arms was abated
around the knight and the gate, leaving only a wall with towers, where
there formerly was also a rampart.

Laszewski
is a direct connection to v.
Silberschwecht Concordance of polonisierter German aristocracy names in
west Prussia starting from 1400
German surname before the polish takeover v.
Silberschwecht Polish name after 1500 Laszewski
see the the defeat of the Teutonic knights at Grunwald/Tannenberg
(1410):
The number of the Teutonic Knights never exceeded a thousand, but the
whole country was organized in a military manner, and with the constant
arrival of new crusaders the order was able to hold its own among its
neighbors, especially the inhabitants of Lithuania, who were of the same
race as the natives of Prussia and, like them, pagans. In the battle of
Rudau (1307) the Lithuanians were driven back, and they were converted
only some years later, with their grand duke, Jagellon, who embraced Christianity
when he married the heiress of the Kingdom of Poland (1386). With this
event, which put an end to paganism in that section of Europe, the Teutonic
Knights lost their raison d'être. Thenceforth their history consists
of incessant conflicts with the kings of Poland. Jagellon inflicted on
them the defeat of Tannenberg (1410), which cost them 600 knights and
ruined their finances, in order to repair which the order was obliged
to have recourse to exactions, which aroused the native nobility and the
towns and provided the Poles with an opportunity to interfere against
the order. A fresh war cost the order half its territory and the remaining
half was only held under the suzerainty of the King of Poland (Treaty
of Thorn, 1466).

This means
v. Zelberschwecht or v. Silberchwecht and Laszcwski
are the same.

Laszewski
comes from from the Estate LASZEWO, ski means from, so
LASZEWSKI means from Laszewo. ski is the polish nobel version
of the German v. or von before the family name. (Pictures and map soon
to come) also Lascewski, Laczewski.

This means
anyone with the name Laszewski is a direct descendant from the knight
Silberschwecht, with the various dialect different pronunciation came
up thus also the von Zelberschwecht.

Before 1400
it was v. Silberschwecht now von and I will need to learn the difference
between the 2 versions.

There is a direct relationship between Grzymala since that was
the battle cry of the Selberschwecht knight and his clan was "Grzymala"
the direct translation of Grzymala is Thunder in English.